Power shovel



w. w. SLOANE juiy 2, 1935.

POWER SHOVEL Filed Aug. 8, 1931 15 Sheets-Sheet l W. W. SLOANE July 2,1935.

POWER SHOVEL Filed Aug. 8, 1931 15 Sheets-Sheet 2 W. W. SLOANE July 2,1935.

POWER SHOVEL Filed Aug. 8, 1931 15 Sheets-Sheet 5 Jufiy 2 135. W, SLQANE2,006,607

7 POWER SHOVEL Filed Aug. 8; 195 15 Sheets-Sheet 4 l juiy 2, 1935 w. w.SLOANE 2,006,607

POWER SHOVEL Filed Aug. 8, 1931 15 sheets-sheet 5 Eye/I751" 7027/22? l].1/03/16 My.

July 2, 1935, v w. w. SLOANE POWER SHOVEL FiledvAug. 8, 1931 };5Sheets-Sheet 6 July 2, 1935. w. w. sLoANE' POWER SHOVEL File A g- 8,1931 15 Sheets-Sheet '7' juiy 2, 1935. SLQANE 2,006,607

POWER SHOVEL Filed Aug. 8, 1951 15 Sheets-Sheet 8 Jufiy .2, 1 935. W,SLOANE 2,006,607

- POWER SHOVEL Filed Aug. 8, 1931 15 Sheets-Sheet 9 Juiy 2, 9 v I w. w.SLOANE v 2,006,607

POWER SHOVEL Filed Aug. 8, 1931 15 Sheets-Sheet 10 ma/for 71/50/11ldJ/oorlt W. W. SLOANE July 2, 1935.

POWER SHOVEL Filed g. 1931 15 Sheets-Sheet l2 n u z w x Z w 9 m d J ly93 w. w. SLOANE 2,006,607

POWER SHOVEL Filed Aug. '8, 1931 15 Sheets-Sheet l5 Patented July 2,1935 I UNITED STATES PATENT OFFICE POWER SHOVEL William W. Sloane,Chicago, 111., assignor to Goodman Manufacturing Company, Chicago, 111.,a corporation of Illinois Application August 8, 1931, Serial No. 555,943

20 Claims. (Cl. 214-90) My invention relates to improvements in powersectional view showing certain details of my inshovels particularlyadapted to operate in convention; fined spaces, such as are encountered.in mines, Figure 14 is a partial enlarged plan view of although notlimited to this use alone. the rearward portion of the device embodyingmy The general objects of the invention reside in invention with-partsbroken away and in section 5 the provision of a power shovel which isadapted to more clearly show the details of my invention; to efficientlyscoop and discharge material in Figure 15 is a sectionalv view taken online confined spaces, such as are encountered in 5 5 f F u mines, allwith-a view towards ease and simplicity Figure 15 is a e g fragmentarySide in operation, compactness, convenience, adaptavation of therearward portion of the device em- 10 bility, high production andgeneral all around efbodying my invention showing certain detailsficiency. thereof;

Other objects of my invention will appear Figure 17 is an enlargedsectional view taken from time to time as this specification proceeds.on line I'L-l'i of Figure 14;

5 My invention may be more clearly understood Figure 13 is a p V Of a aof Valves With reference to the accompanying drawings used in the deviceof my invention with parts herein: 7 broken away and in section to showthe details Figure 1 is a side elevation of the device of my t Iinvention; Figure 19 is a side, elevation of the gang of 20 Figure 2 isan enlarged plan view of the forward valves shown in Figure 18; 20portion of the device embodying my invention Figure 20 is a fragmentaryp View Of the with parts broken away and in section; gang of valvesshown in Figure 18 with parts Figure 3 is an enlarged plan view of therearbrokenaway and in section to show the fluid presward portion of thedevice embodying my 'invenu C u t u the Valve manifold;

tion with parts broken away and in section; Figure 21 is a sectionalview taken on line 2 |-2| 25 Figure e is an enlarged side elevation ofthe of Figure forward portion of the device embodying my in- Figure 22is a diagrammatic V w s w the vention with parts broken away and insection; fluid pressu Circuit through the gang o Va v Figure 5 is anenlarged side elevation of the shown n Figure rearward portion of thedevice embodying my in- Figure 23 is a P a fragmentary D p a 30 ventionwith parts broken away and in section; View a D 0f e ev of y inventionFigure 6 is an enlarged side elevation of the with parts broken w y andin section h w forward portion of the device embodying my i the detailsof certain other of the valves. used vention with parts broken away andin section in the hydraulic y 7 i i and showing the device in adifferent position Figure 24 is a sectional View taken on line 35 thanin Figure 4; 24-24 of Figure Figure '7 is an enlarged fragmentary sideele- Figure is sectional View taken n line vation of the forward portionof the device em- 25 f25 of Flgure i and bodying my invention with partsbroken away Figure 26 1S e m q Vlew of entire 40 and in section to moreclearly show the details of pressure Olmult of the cievlce of myInvention 49 Like numerals refer to like parts throughout my mventlonthe various figures a v c t j, i j pif i i g jz g fi j t Referring nowin particular to the drawings, I

a y on e i designates a power shovel of thetype embodying 4' Figure 9 ISn enlarged sectlonal vlew taken my invention which is supported on abase frame on 9 Flgure 2; t 2. The base frame 2 in turn is mounted forpro- I Flgm'e is a enlarged partlal sectioned pulsion on suitablelaterally spaced continuous substailtlally hne of Flgure 2; treaddevices 3. A turntable 4 supports the figure 11 18 an emergedfragmentary v of major part r the shovel'operating mechanism 50 therearward portion of the device embodying and is rotatably supported onthe base frame 2 50 invention showing certain details of my in-' on anupright ring 5 and bearing pads 6 disposed vention; I V forwardly andrearwardly of said turntable.

Figure 12 is an enlarged partial transverse sec- Theturntable ecomprisesa platform I having tional view taken on line l2l2 of Figure5; a largecentral bore 8 therein. A flanged bush- Figure 13 is an enlarged partialfragmentary ing 9 is freely mounted within the bore 8 of the 55 platformI. This bushing is so disposed that the flange of said bushing abuts arecess on the top side of said platform. A gear I0, having its bottomface abutting the flange of said bushing, is provided with a shoulderjournaled within said bushing and a hub I I journaled on a sleeve I2freely mounted on a vertical shaft I3 disposed centrally of the baseframe 2. The gear I0 is fixed to the base frame 2 by means of suitablecap screws in an ordinary manner (see Fig. 9). Thus the lower face andshoulder of the gear I0 prevent tipping of the platform 1 and turntable4 and said turntable is journaled within the bushing 9 for rotationabout the axis of the vertical shaft I3. A pinion I4 driven from asuitable mo.- tor I5, herein shown as an electric motor, in a mannerwhich will'hereinafter be fully described,

. sides thereof. fixed on a member 26 adjacent one side of the mesheswith'the gear ID for driving the platform 1 around said gear.

Mounted on opposite sides of the platform I on the extreme forward endthereof is a pair of downwardly facing vertically disposed fluidpressure cylinders I6 containing pistons Il having feet I8 on theirlower end so arranged that the 'pistonsmay' 'be lowered by fluidpressur'inthe cylinders to engage the feet I8 witha fixed part such as amine. floor, thus forming a means for leveling the power shovel andholding th'ebase frame 2 and power shovel I in a steady position duringthe loading operation. Said cylinders will hereinafterbe called levelingcylinders. I v

The feet I8 are disengaged from the groundby meansof fluid pressurecylinders mounted on oppositesides of the underside of the platform Iand extending rearwardly from the cylinders I6. Each fluid pressurecylinder 20' is provided with a piston 21 having ajbra cket 22 fixed toits outer end. The bracket. '22 is provided with a plurality ofsheaves23. Another pair of sheaves 24 are provided adjacent eachcylinder IE on opposite A flexiblecable has one end cylinder 20. Thiscable extends rearwardly from the member 25 around one sheave 23 andfor- .wardly around one sheave 24 and downwardly arounda, groove 21 inthe foot I8 of the piston I!. This cable extends from said groove on theopposite side of the foot I8 upwardly around the other sheave 24 andrearwardly and around the sheave 23, from whence it extends forwardly tothe member 26.-

The cable 25 has its end fixed to the member 26 on theopposite side ofthe cylinder 20 from said first mentioned end of said cable so whenpressure is applied to the piston 2| the foot !8 will be raised in anobvious manner. These cylinders '20 will hereinafter be termed footlifting cylinders. The cylinders I6 and 20 are operated by fluidpressure in a manner which will hereinafter be more fully described andthe valves for operating said cylinders are interconnected with theturntable operating levers so the feet I8 may be disengaged from theground as the turntable 41s turned about its axis. This means ofinerconn'ecting thevalves for operating the cylinders I6 and 20 with theturntable 4 will hereinafter be more fully described.

'1 The platform I is provided with a sliding frame 29' which supports aconveyor generally indicated at 38; The conveyor30 may be of any typewell known to the art but is herein preferably shown as being areciprocating or jigging conveyor of a type well known to those familiarwith the art. The conveyor 38 is provided with a scoop 3| and has itsforward portion hinged so said scoop may thereof and extends the entirelength of the platform 1 and is provided with a pair of upstanding sidewalls 33 on opposite sides thereof rearwardly of said aforementionedcut-away portion, which side walls form a slidable support for the"conveyor 30.

Support members 34 extend horizontally outward from opposite sidesof theside walls 33 adjacent the lower portion thereof for substantially theentire length of said side walls and have slidableengagement withshoulders 35 on the platform 1. A retaining strip 3I5 is attached to theplatform l andabuts the top portion of each support member 34 and formsa sliding guide for said supportmembers so the sliding frame 29 maybeslidably moved longitudinally of said platform a Means are providedfor moving the sliding frame 29 on the platform I, which means are Zherein preferably shown as being hydraulically operated. Said meansinclude cylinders 31 mounted on opposite sides of the platform Iadjacent the inner sides of the cylinders I6. The

forward end of each cylinder 31 is fixed in a bracket 38 fixed to eachcylinder IS. A piston 39 is provided for each cylinder31 and extendsrearwardly therefrom; The rearward end of each piston 39 is fixed to theupstanding side walls 33 of the sliding frame 29 by means of brackets4|. These last mentioned cylinde be referred was in-cylinders;

A pair of cylinders 43 are flxed to upstanding 'supp'ortmembers (whichsupport members are fixed to theplatform 1 adjacent the rearward endthereof. These cylinders extend forwardly from the upstandingsupportmembers 44 and are prors will hereinafter I vided with. pistons 45therein. The pistons 45 have their forward ends fixed in members 48extending'outwardlyfrom opposite sides of the upstanding sidewalls 33.These last mentioned cylinders will hereinafter be referred to as theoutcylinders.

As fluid pressure is applied to the cylinders 43 the sliding frame 29 ismoved forwardly along the platform I to move the scoop 3 Iv intothemate: rial to be loaded. As pressure is applied to the cylinders 37 thesliding frame 29 may be moved rearwardly along the platform I andreturned to its initial position on said platform.

Referring now in particular to the conveyor 38 V and means forsupporting said conveyor for re 'ciprocable movement longitudinally ofthe power shovel and for supporting its rearward end for verticaladjustment with respect to the ground,

said conveyor comprises a chute 41 extending longitudinally of the powershovel beyond the forward and rearward ends of the platform I; The chute41 is supported on the upstanding sidewalls 33 of the sliding frame 29,for slidable movement with respect thereto, by angles 49 fixed toopposite sides of the underside thereof having their legs ex-- tendingdownwardly from the inner side thereof. These angles engage the topportion of the upstanding side walls 33 for guiding the conveyor chute41 for reciprocable movement along said side walls.

Angles 58 are fixed to opposite sides of the conveyor chute 41 adjacentthe lower end thereof. These angles have their legs extending outwardlyand are engageable with a vertically movable member 5| supported forvertical movement in the upstanding support members 44 (see Figs. 14, 15and 16).

The vertically movable member 5| is pivotally supported on a block 52having guide grooves on each side thereof, which guide grooves areengaged by vertically extending guides 54 in the upstanding supportmembers 44. A flexible cable 55 is fixed to the outer side of the lefthand block 52 and extends upwardly therefrom around a sheave 51supported in the upstanding support member 54 adjacent the upper endthereof. The cable 55 extends downwardly from the sheave 5? around asheave 58 adjacent the lower end of the upstanding support member 54 andtransversely toward the opposite side of the machine where it has itsend fixed to one side of a rnem ber 59. The member 59 is fixed on theouter end of a piston 69 mounted in a transversely extending fluidpressure cylinder 5% and has a tongue 62 extending downwardly therefrommovable in a transversely extending groove 63 formed in the platform I.

A flexible cable 65 has one end fixed in the opposite side of the member59. This cable extends along the cylinder 6| and around a sheave 85 andalong said cylinder in an opposite direction to a sheave 61 supportedfor movement about a horizontal axis adjacent the lower end of theupstanding support member 14, from thence the cable 65 extends upwardlyalong said upstanding support member around a sheave 68 and dowi wardlywhere it has its end fixed in the outer side of the opposite block 52.Thus it may be seen that as fluid pressure is applied to the fluidpressure cylinder 6|, the blocks 52 are moved vertically along theupstanding support members M, which movement in turn causes verticalmovement of the conveyor chute 41 and forms a means for adjusting therearward end of said conveyor chute to the various desired car heights.

The forward portion of the conveyor chute 4'! is provided with a hingedsection 69 A plate It! extends forwardly from and is hinged to theforward end of the hinged section 69. A plate H extends forwardly fromand is hinged to the forward end of the plate Til, and another plate '52extends forwardly from and is hinged to the forward end of the plate H.

The plate 12 is supported on the scoop 3| for slidable movement withrespect thereto by means of depending guide members l3 engaged by slots14 in the scoop 3!. Likewise, the piate if! has depending guide members15 engageable with slots 16 in a pivotally movable support frame it. Thehinged section 69 of the conveyor chute :3! is provided with dependingguide members l9 engageable with longitudinal guides in a support frameextending rearwardly of the pivotally movable support frame H. Thesupport frame 80 is pivotally supported at its rearward end on thesliding frame 29 by a transversely extending shaft 8 i, and thepivotally movable support frame 1! is pivotally supported on its forwardend by means of a transverse shaft 82.

A shaft 83 is fixed in the forward portion of the pivotally movablesupport frame 11 and has its ends extending outwardly from each sidethereof. A thrusting beam 84 is journaled on each of the outer ends ofthe shaft 83; These beams extend forwardly and rearwardly of the shaft83 and have their forward ends fixed to the outside of the scoop 3|.When the scoop 3| is in a downward position adjacent the mine bottom, orbeneath the mine bottom as is illustrated in Figure 4, the thrustingbeams 34 extend upwardly from the shaft 83 to the upstanding side walls33 of the sliding frame 22 along said side walls on theouter sidesthereof to a point rearwardly of the continuous tread devices 3.

A yoke '85 is mounted within the upstanding side walls 33 for movementlongitudinally thereof. The yoke 85 is provided with outwardly extendingbosses 85 adjacent the forward ends thereof, which bosses extend throughlongitudinally extending slots 81 in the upstanding side walls 33 of thesliding frame 29. The ends of these bosses extend outwardly beyond theupstanding side walls 33 and have the thrusting beams 84 pivotallymounted thereon in a suitable manner well known to those familiar withthe art (see Fig. 3).

The rearward end of the yoke 85 has pivotal connection with a member 88adjacent its central portion. The member 88 is connected with anintermittent thrust imparting mechanism 85 in a manner which willhereinafter be more fully described, so operation of said mechanism willtransmit an intermittent thrusting action to the scoop 3| for forcingsaid scoop under large pieces 7 of material when a predeterminedpressure has been exerted on the forward edge of said scoop. When thescoop 3| is resting on the ground and it is desired to gather material,pressure is exerted on the pistons 45 in the out-cylinders 23. Thismoves the sliding frame 29 a distance equal to the length of the slot82. When the sliding frame has moved this distance the rear end of theslot 87 engages the bosses 85 and exerts a pressure on the thrustingbeams 8 which forces the scoop 3| into the material. When large piecesof material are encountered which cannot be gathered by the scoop 3| anda predetermined pressure has been exerted on said material by theout-cylinders 43 the intermittent thrusting mechanism 89 automaticallycomes into action and imparts a ham- .rnering movement on the scoop 3|to break up said material a manner which will hereinafter be described.

Referring now in particular to the mechanism for raising the scoop 3|and elevating the conveyor 3 3 to a substantially horizontal position somaterial can be moved along said conveyor and discharged to a suitablereceptacle such as a mine car, a plurality of longitudinally extendingfluid pressure cylinders 58 are mounted on the sliding frame 29 forslidable movement with respect thereto. These cylinders will hereinafterbe referred to as digging cylinders since they impart a digging as wellas lifting action to the scoop 3i and are provided with rearwardlyextending pistons 85, which pistons abut and are fixed to a shoulder 93of the sliding frame 23 so the entrance of fluid pressure into thecylinders will cause longitudinal movement of said cylinders along thesliding frame 29.

The fluid pressure digging cylinders Si) are connected together by meansof a connecting member 9t provided with machined bosses 95 on the outerends thereof. Each of theseibosses has a connecting rod 9? pivotallymounted thereon. The opposite ends 'of the connecting rod 51 have pivotal connection with a shaft 98 adjacent the outer end thereof which isjournaled in an elevating frame 99. 1

The elevating frame 99 extends transversely of the power shovel and hasa portion I89 which extends downwardly andrearwardly from the shaft 98when the conveyor 39 and scoop 3| are p in an elevated position, as isshown in Figure 6.

The lower portion of the portion I99 of the elevating frame 99 is of anarcuate shape and has bearing engagement with a bearing pad I9| on thesliding frame 29 as said elevating frame is operated by the diggingcylinders and necting rods 91. i

The upper or forward portion of the elevating frame 99 is pivotallyconnected to the transverse shaft 82. and thus has connection withthesupport frame 89 and the pivotally'movablesupport frame TI, and has ashoulder I9! which is adapted to engage a support I08 depending from thepivotally movable support frame Tl.

It may thus be seenthat the application of fluid pressure to the diggingcylinders 98, effects forward movement of said cylinders along thesliding frame 29 which moves the elevating frame 99 about the axis ofthe shaft 82 by means of the connecting rod 9?. This pivotally moves thepivotally movable support frame ll about the axis of the shaft 82 andraises said support frame and the thrusting beams 84 to raise the scoopand move said scoop to a substantially horizontal position. When thepressure is released from the fluid pressure digging cylinders 99, thescoop 3| moves downwardly to engage the mine bottom by means of gravity.

, Additional means are provided for elevating the scoop 3| when in alowered position. Said means herein comprise an upwardly extending fluidpressure elevating cylinder I89 disposed adjacent the forward centralportion of the sliding frame 29. The fluid pressure elevating cylinderI59 provided with a piston H0 adapted'to engage a bearing pad IIIdepending from the support frame 88. Upward movement of the conveyor 30and scoop 3| effected by the elevating cylinder I99 and piston III) islimited by straps H2 pivotally connected to opposite sides of thesupport frame'fifl. These straps H2 have inwardly extending pins I3adjacent their lower ends which engage slots H4 in the forward portionof the upstanding side walls 33 of the sliding frame 29 and thus limitupward movement of the support frame 88.

When the scoop 3| is in a lowered position and is wedged under a largepiece of the material which cannot be lifted or dislodged by means ofthe fluid pressure-digging cylinders 90 and elevating frame 99, theapplication of fluid pressure to the cylinder I09 will cause upwardmovement of the piston III! which will in turn move a link I93 upwardlyand elevate the entire scoop 3| to dislodge said material and releasesaid scoop. aid cylinder may also be brought into operation when it isdesired to lift the scoop for loading along an uneven bottom or from abench on the bottom.

. Referring now in particular to Figures 3, 5, 11, 12 and 13 and thedetails of the thrusting mechanism 89 which is arranged to impart anintermittent thrusting action on the forward edge of the scoop 3| whenthe pressure in the out-cylinders 43 reaches a certain predeterminedvalue as has hereinbefore been mentioned, said thrusting mechanismincludes a frame II5 having tongues I I8 extending outwardlyfrom eachside thereof near thelower portion thereof. The tongues I I6 are adaptedto engage grooves III in the sliding frame 29 so the frame.||5 may bereclprocably moved longitudinally of the sliding frame 29. A motor H8 isprovided on the sliding frame II5. This motor may be of any type but isherein preferably shown as being an electric motor and has a. bevelarmature pinion 9 which meshes with and drives a bevel gear I20 fixed onthe upper face of a flywheel I2I. The flywheel |2| isfixed on a verticalshaft I23, which shaft is journaled in the frame 5 at its lower end andin a cross-member I24 extending across the frame I I5 at its upper end.A cam I25 is keyed on the vertical shaft I23. This cammay be ofanysuitable form to impart the required intermittent'thrusting action tothe scoop 3| but is herein preferably shown as being circular in formmounted eccentrically of its center on the vertical shaft I 23. The camI25 is made of two parts which include an upper part and a lower part.The lower part of. said cam is engaged by a roller I2'I disposedrearwardly of the vertical shaft I23 whilethe upper portion of said camis enga ed by a roller I28 disposed forwardly of the vertical shaft I23.

reciprocatory movement to, the yoke 85 or to cause the frame H5 toreciprocably move with respect to the frame 29 when said yoke is heldfrom movement. p

The roller I2'iv is mounted on a pin I29 by means of suitable ballbearings in a usual manner. The pin E29 is held in the member at its topand bottom ends,'which member has pivotal connection with the yoke 85 ashas-hereinbefore been mentioned. The top portion of the member 88extends forwardly of the yoke 85 and around the, shaft I23 and formsabearing support for the roller I28 which is mounted on the forwardportion of the member 88. vided with tongues I39 which ride in groovesformed by shoulders on the top portion of the frame I I5 and thecross-member I24 which is fixed to the top portion of said frame (seeFigs. 12 and 13). It may now be seen that rotation of the flywheel I2|tends'to cause reciprocatorymovement of the member 88 which tends. toimpart reciprocatory movement to the yoke 85. As the scoop 3| is movedinto the loose material bythe out-cylinders 43 and engages anobstruction which cannot safely be picked up by the action of said therearward end of the slots 87 movement of the sliding frame 29 will causemovement of the scoop 3|. When the scoop 3| abuts'an immovable piece ofmaterial and the motor I I8 has been automatically started, theintermittent thrusting mech-' anism 89 moves reciprocably longitudinallyof the sliding frame 29 in the grooves III due to the fact that thescoop 3| abuts the immovable piece of material. ing action to betransmitted to the scoop 3| through the yoke 85 and thrusting beams 84.This intermittent thrusting action advances the forward end of the scoop3| into the material and either wedges said scoop under the material orbreaks the material up so it may be picked up and loaded into theconveyor 30 by said scoop. The cam I25 is so arranged that the greatestforce is I The rollers I21 and I28 areinterconnected so as'to impart Themember 88 is pro- This causes an intermittent thrustexerted when theintermittent thrusting mechanism 89 is moving forwardly along thesliding frame 29. This imparts an intermittent thrusting action to thescoop 3| and counterbalances the reaction of the thrusting beams againstthe shovel frame and this additional force prevents said thrustingmechanism from moving the entire shovel rearwardly.

It should be understood that the intermittent thrusting mechanism 89normally is inoperative and when loading loose material the cycle ofloading is carried on without the use of said inter mittent thrustingmechanism. This intermittent thrusting mechanism only comes intooperation where the material to be loaded is of such size and texturethat it cannot be loaded by means of the pressure exerted by theout-cylinders 43. It may thus be seen that during operation of saidthrusting mechanism the out-cylinders 43 are continually exerting apressure on the scoop 3I to force said scoop under the material, andthat said thrusting mechanism is merely an auxiliary means to be used inconjunction with said outcylinders to aid in breaking up and loadinglarge pieces of material or material tightly wedged between the roof andbottom of the seam.

Referring now in particular to the conveyor and means for reciprocablymoving said conveyor to move material from the'forward to the rearwardend thereof, suitable reciprocatory drive mechanism generally indicatedat I33 is provided for reciprocably moving the conveyor chute 41 (seeFig. 3). This reciprocatory drive mechanism includes a crank I34 drivenby a motor E35 through a suitable gear train generally indicated at I35.A connecting rod I31 connects the crank I34 to a cross-head I38. A bari39 is supported in the cross-head I38 and extends transversely of thesliding frame 29. A connecting arm Me is connected to each of the endsof the bar 53-9 and extends rearwardly therefrom. The rearward ends ofthe connecting arms I40 are pivotally connected to a lever arm I4Iadjacent the central portion thereof. The lever'arm M! is pivotallysupported at its 'lower end on the sliding frame 25 while the upper endof said lever arm is connected to the conveyor chute 41 by means of aconnecting link I43 in a usual manner. The crank I34 is so arranged thatthe conveyor chute 41 moves faster in'a forward direction than in arearward direction so as to move the material rearwardly along saidconveyor chute in a usual manner and thus operation of the motor I35reciprocably moves the conveyor chute 41 to transfer loose materialrearwardly along said conveyor chute in a manner well known to thoseskilled in the art.

The conveyor chute 41 is provided with a gate 44 at its rearward end.The purpose of this gate to provide means for loading the entireconveyor chute 41 before discharging the material into a receptacle.This forms a means. for storing the material which is being loaded sothe loading operation may be continued when the supply of cars has beenexhausted. The motor I5 forms an actuating medium for driving thecontinuous tread devices 3 and mov the power shovel I about the mine,for turning the turntable 4 about its axis, and for supplying fluidpressure to the fluid pressure sys-'- tem, the details of which willonly be described insofar as is necessary to fully disclose my presentinvention. A longitudinally extending horizo'n tal drive shaft M5 isprovided on the right hand side of the machine and is driven from the motor I5 by means of a gear train indicated at I46.

The rearward end of said shaft has driving conjnection with a suitablefluidpressure pump I41,

through an internal gear I48 having operative connection with said pumpand a pinion I49 keyed on the rearward end of said drive shaft. Thefluid pressure pump I41 is of a usual threes cylinder construction of atype well known to those skilled in the art so will not herein bedescribed in detail, and is used to provide a high pressure for thefluid pressure system.

The hydraulic system for controlling the various movements of thehydraulically operated parts will now be described. p

In the device of my invention the main functions such as digging,crowding, etc., are operated at a relatively high pressure, whilecertain other functions; as, for instance, the operation of the highpressure valves, means for controlling the operation of the turntable 4and continuous tread mechanisms 3 are operated at a lower pressure. Inthe high pressure system the pump I41, driven by the electric motor I5,serves to effect the pressure. The connection from this pump to thevarious actuating parts of'the system are effected through valvemeansiwhich, as shown, consist of platform valves generally indicated at240 and digging and elevating valves generally indicated at 24I and 242.The platform valves 24!! and digging and elevating valves 24I and 242are in turn operated through suitable connections by means of a separatelow pressure circuit including low pressure fluid pressure valveoperating cylinders and low pressure valves. The low pressure valvesconsist of gang valves for operating the digging and elevating valvesgenerally indicated at 243. Low pressure foot valves generally indicatedat 244 are provided for controlling the operation of the turntable, andthe connections therefrom will not herein be described in detail sincethey are no portion of my present invention. 4

A pump 245 driven by the electric motor I5 through the shaft I and geartrain generally indicated at 246 serves to eiiect the pressure in thelow pressure system. The connections from this pump to the variouscylinders for actuating the high pressure valves and actuating parts ofthe low pressure system are effected through the gang valves 243 andfoot valves 244.

Referring now in particular to the low pressure fluid pressure system,the fluid circulates from the pump 245 under pressure through a pressurepipe 241 which connects with apressure equalizing tank 249 (see Fig.26). From thence a pipe 250 connects with the pressure side of themanifolds for the gang valves 243 and foot valves 244. A return pipe 25Ileads from the exhaust side'of the manifolds for said gang and footvalves to a fluid pressure storage tank 253. The fluid pressure storagetank 253 serves as a reservoir for both the high and low pressuresystems and has connection with the intake side of the pump 245 by meansof a pipe 254.

The pressure equalizing tank 249 is provided with an inlet and outletnear the bottom end thereof and an air chamber above the fluid toequalize the fluid pressure in the pipe 250 and prevent surging in saidpipe line upon operation of the pump 245. This provides an even pressureto the low pressure gang and foot valves 243 and 244 and enables thehigh pressure valves and low pressure mechanism to be positivelyoperated through pistons actuated by fluid in thelow pressure system atall times. A safety valve 255 is

